This invention relates to data processing apparatus and, more specifically, is concerned with controlling the performance of such apparatus.
It is sometimes required to adjust the performance of a data processing system to a desired level, less than the maximum potential performance of the system. For example, if a user requires only a limited performance system, a manufacturer may offer to supply a higher performance machine, modified so that its performance is reduced, at a lower price than is normally charged for this machine. The advantage to the user is that he gets a machine with the desired performance and price, with the possibility of upgrading the machine at some later date upon payment of an agreed fee to the manufacturer. The advantage to the manufacturer is that he can use a single hardware design to cover a number of different performance levels.
The object of the present invention is to provide a novel way of controlling the performance of data processing apparatus.